Will stem cell therapy replace Tommy John surgery for baseball players? Angels pitchers may find out

Angels pitcher Andrew Heaney calls a trainer to the mound as he suffers a nose bleed while pitching against the Chicago Cubs on April 5, 2016.
(Robert Gauthier / Los Angeles Times)

Twice now, doctors have performed an ultrasound on Andrew Heaney’s arm, squirting on a gel, twisting it around, taking pictures, and then showing him the images on a screen.

He doesn’t entirely understand what he sees, but it’s enough to inspire hope in the 25-year-old Angels pitcher.

The ulnar collateral ligament in his left arm, which tore and abruptly ended his season after one appearance, looks like it is healing. To what extent is yet to be determined.


Heaney experienced pain near his elbow during an April 5 start against the Chicago Cubs, but no one knows precisely when the fibrous tissue actually ripped. At first, the Angels prescribed rest and physical therapy. When that didn’t help, he was left with a choice:

Undergo ligament replacement, a proven procedure commonly known as Tommy John surgery, that probably would keep him out of action for 15 months or more; or try something different.

He chose stem cell therapy.

Undergoing stem cell treatment might allow him to return to the Angels’ rotation by the end of this season, Heaney was told. So he took a calculated risk and visited the Kerlan-Jobe Orthopaedic Clinic, where stem cells from his own bone marrow were injected into his left elbow.

Two weeks later, in mid-May, Garrett Richards, the Angels’ 28-year-old ace right-hander, underwent the same procedure for a partial UCL tear similar to Heaney’s.

Since then, as the Angels slid into last place, 17 ½ games behind the Texas Rangers in the American League West, all the team’s top two starters have been able to do is watch as they wait to see if their ligaments regenerate.

“It just requires patience. It’s not any deeper than that,” Angels General Manager Billy Eppler said. “You don’t play mind games with yourself, you don’t bang your head against a wall — you just wait.”


The ultrasounds show, to a certain extent, the rate of healing in the injured area. What’s not known is how much of a partially torn ligament stem cell therapy will actually repair.

“We do know stem cells can heal tissue and form new tissue. It can work,” said Dr. Tim Kremchek, an orthopedic surgeon who is the Cincinnati Reds’ team physician. “The question is, can it work to the level we want it to for these pitchers, in their elbows?”

Another key question: “How long do you wait until you realize it doesn’t work?” asked Dr. David Altchek, an orthopedic surgeon who is the New York Met’s team physician. “If it turns out you were wrong and you waited four, five months, then what?”

Then, the only alternative is surgery. But wasting a few months was worth the risk for Heaney and Richards because had they chosen surgery immediately they would have missed this season and also, likely, most if not all of 2017.

In 1974, Dr. Frank Jobe performed the first UCL replacement surgery on Dodgers pitcher Tommy John. The soft-throwing left-hander returned after 18 months, and for decades his rehabilitation provided a blueprint that was continually shortened. At one point, the industry standard for full recovery was less than a year.

More recently, most pitchers who have undergone the procedure have taken 15 months or more to complete their comebacks. Angels left-hander Tyler Skaggs had surgery 22 months ago and is still working his way back in with a low-level minor league team.

Given the old 12-month recovery prognosis, Heaney said he would have chosen surgery. Richards wasn’t as certain, but, like Heaney, he believes that trying stem cell therapy was gambling with free time.

I feel like I take up I’m not providing any kind of use to the team

— Injured Angels pitcher Andrew Heaney

Both players live near Anaheim and attend all the Angels’ home games, and both are working out to stay in shape. They’re just not throwing yet, and that’s the most frustrating part.

“I feel like I take up space,” Heaney said recently. “Like I’m not providing any kind of use to the team.”

The process can be just as infuriating for physicians.

Outside the United States, doctors have administered small doses of human growth hormone and other so-called “growth factors” on stem cells to grow ligament tissue in labs before injecting them into a patient. But HGH is prohibited by Major League Baseball’s drug program, and the use of growth factors is banned domestically by the Food and Drug Administration.

Dr. Joseph Purita, who says he has performed stem cell therapy on about two dozen pro pitchers, including Bartolo Colon, laments that for these reasons he is able to provide better care for a baseball fan than he can for a baseball player. “It’s a real moral dilemma for me,” he said “… I should give the best care I possibly can.”

At its core, most stem cell therapy isn’t complicated. The procedure takes about 20 minutes from start to finish. With recipients under anesthesia, bone marrow is harvested from the pelvis and spun down in a centrifuge, producing a liquid with a high concentration of stems cells. For Heaney and Richards, those cells were then injected into the elbow.

“This is natural,” Heaney said. “You use your body’s natural ability to heal itself and speed [the healing process.] Why not?”

If Heaney and Richards can return to the Angels’ rotation while avoiding surgery, more injured pitchers may choose stem cell therapy.

For now, skepticism reigns because of the many unknowns.

“We’ve put so much stigma on therapies and treatments that it’s really become, like, a witch hunt,” Angels closer Huston Street said. “There’s an amount of care that guys have to take with who they trust and how they trust — because God forbid you go to a doctor that has a license to sell HGH and he’s got a whole client list of 50-year-olds that want to stay young and your name is on that list.”

Street speaks from experience. In 2010, federal investigators interviewed him about time he spent in Toronto three years earlier, when he underwent oxygen therapy and platelet-rich plasma therapy from Dr. Anthony Galea.

Street, then the closer for the Oakland Athletics, had been diagnosed with an irritated ulnar nerve. His arm recovered after 18 days of therapy, but investigators questioned him as they looked into Galea, who in 2011 pleaded guilty to a felony charge of carrying unapproved drugs into the United States to treat athletes. Street was never accused of wrongdoing.

There’s also the matter of whether stem cell therapy actually works in some situations. For example, evidence suggests it will not work on full tears. Altchek, the Mets’ physician, has developed an algorithm that he says helps him determine the chances of the therapy working based on where the tear occurred within the ligament — better high than low.

Dr. Henry Stiene, a Cincinnati-based surgeon who works with the Reds, believes the therapy will have a larger effect on labrum tears in throwing shoulders, which often prove difficult to surgically repair.

“That would be the ultimate in baseball,” Stiene said.

If Richards and Heaney show more improvement, they could begin a standard throwing program in August. That would put them six to 12 months ahead of what their schedule might have been after surgery. However, they would still not know if the stem cell therapy worked.

“The problem with partial tears,” Stiene said, “is they’re not symptomatic until they get about 75% effort level.”

That’s the uncertainty the Angels and their pitchers are confronting. The ligaments are healing, but to what degree is unknown — and won’t be known until they start throwing again.

If they do make a full comeback, Heaney and Richards could become the poster players of a revolution in arm rehabilitation.

C.J. Nitkowski, a journeyman left-hander who five years ago underwent stem cell therapy in a last-ditch attempt to extend his career, predicted the procedure might become an annual event for some pitchers.

If it ever becomes conclusive that your own stem cells can help you regenerate ligaments, then why wouldn’t you do it every off-season?

— Former MLB pitcher C.J. Nitkowski

“If it ever becomes conclusive that your own stem cells can help you regenerate ligaments, then why wouldn’t you do it every off-season?” he said.

Street sees the potential, but proposes caution. “It behooves the player to be transparent with their organization — what they’re doing, who they’re seeing,” he said. “And the smart organizations are going to be an incubator to their players in those regards, educating them so they can control it better.

“Because as we’ve seen, players will make mistakes. What if a doctor just wants to prove that he can heal you and slips [a banned substance] in there?”

Heaney and Richards will wait and see, just like the rest of the Angels.

“Maybe I’ll be a medical miracle,” Richards said last week. “But if I can’t be what I was before, I’m not going to push it. I’ll just have the surgery.”

Twitter: @pedromoura